I installed an electric fan and now it runs hotter!?!?

I just had the same trouble turns out I had a fan with not a enough rpm ..I put one fan on the inside of the rad and one in front of the rad. a push pull set up. Change d the t stat to a 160. Now the car runs at 140 to 160. when I get on it , it goes up to max 200 but than drops as I drive. Heat cranks hot. And no more over heating. And also make sure to bleed the coolant system of air.that will cause a world if trouble , and constant over heating problems. Good luck

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That remark was totally uncalled for. The man in question was a good person, good club member, good husband and father, and died last year from a brain tumer. I don't think I need to tell you what I think of you. Anyone can connect an electric fan backwards.

 

You dont think there could be air in your coolant system? I have heard of guys jacking there car up with the rad cap off to get the air out of the system. Just a thought.

 

Would you describe this 45 degree angle in more detail?

I went by the book about airconditioning authored by the head of vintage air. I located my fan 2/3 in my shroud. I didn't understand why at the time. So finally I'm learning this from you, it will create the 45 degree angle.

I'm in agreement with you on not blowing straight back. Lots of my fellow merc owners feel the air hits that huge fire wall which is a large area, that hood usually sits way above most motors too. So there is one giant pocket to trap hot air.

One guy put in buick port holes in the hood sides to fix his. Another guy mounted fans under his hood, by the fire wall, blowing down to get the air untrapped from that huge space. I've been doing okay I guess by my fan/shroud setup and a huge dodge van radiator in my Merc.

So it's 45 degrees not just looking from the side, but all around the shroud opening, essentially a widening cone of air coming out of the shroud?

 

Thank you Henry III. I could not have stated it better.

 

When you say "cooling tubes" are you referring to the number of "cores". Like a three core or four core radiator?

 

I'll disagree with Dick on the number of fins required in an aluminum radiator.
Aluminum radiators dissipate heat much better than copper radiators, because the aluminum tubes are welded directly to the fins during the construction process (at least Griffin radiators are). Copper radiators have a lead-soldier joint where the fins meat the tubing. While the copper does a good job of transferring heat, lead is an excellent insulator--every joint where fins touch the tubes, has to go through insulation first. Therefore they aren't as efficient, and do not transfer as much heat.

It's been a long while since I've done a story on cooling, but if I remember correctly, the burst pressure of aluminum tubing is higher than copper, which means aluminum tubes can use thinner walls, which allows them to have an oblong shape, and have more surface area than copper tubes. More surface area allows you to run 2 rows where you'd need 3 with a copper radiator.

There is also a theory that by the time the air passes through the first three tubes and reaches the 4th, the air is "saturated" and doesn't wick away any more heat, it just creates an obstruction for the air to pass over, thus hindering airflow and allowing air to stack up--air movement is what cools, so stacked-up air kills efficiency.

That being said, I have a 4-row copper radiator in my daily driver '61 Suburban. I'd like to go with an aluminum radiator at some point, but to be honest, there's no reason to in my vehicle right now--it works well as-is... and that's without the shroud on it yet.

-Brad

 

45 degrees is a rough number.... You want to feel most of the air from the fan near the first cylinders exhaust on either side, but the least at the water pump..... Fan depth in shroud adjusts this.... Reasoning is, if air blows straight back it builds pressure, and will act the same as a flex fan at high way speeds. Not letting any more air pass, or kinds like an air bubble in the pick up truck bed...... 45 degrees is the rough angle to dissipate this pressure via wheel wells, and under carriage.....

On my truck, which had an over heating problem after I installed A/C, I went with a 1957 chevy truck HD radiator.... Its a 2 core (2 3/8s tubes) Brass copper. SInce Brass copper is a better dissipater of heat. I think Brass copper with the right number of fins exceed aluminum by as much as 30%....

With my Brass copper radiator, I now have a problem of running to cool.... Go figure.... 85 and humid, I am struggling to get to 160, and after long traffic time, I get to 170, but then when I start rolling its right back down to 160.... Its not an air flow problem its a pulley problem, I am runnin 1 to 1.... So, my next thing is to enlarge the crank pulley, get a smaller W/P pulley, and then try another 180 degree thermostat.....

It seems 180 is optimal to reduce cylinder wear and aid air fuel mixture....

I never thought I would run cooler with a 2 core stock, but I am....

 

The car is not overheating. Temp will always shoot up when at a stoplight. The fan will come on and cool the area it is blowing cool air. Bear in mind the rest of the radiator that is not getting flow from the fan has now lost the airflow experienced while driving. Hence all the questions on your shroud. Shrouds normally cover the entire radiator. Therefore, the temp will drop some but not like you driving with full airflow. Seems to me you are believing their is a problem when their isn't.

 

I have a big hot 454 in my 58 caddy and I had one if those after market cheapee Pep Boy electric fans on it with no shroud. It constantly overheated so I put an OEM Mark 8 fan in it and it won't dare get past 180. The fan comes with a shroud and I grabbed it off of eBay for 100 bucks. I was pushing it up hills on a 100 degree day and it go to 200 for a second and then the fan came on and pulled the temp down. The right fan and a properly fitted shroud is a must.

 

I don't really see how this can be true. My reasoning is this. Air will always flow from a high pressure zone to a low pressure zone to find equilibrium. The bottom of the engine compartment isn't sealed. So if the fan could generate any pressure in the engine bay, it would easily leak out the bottom and under the car. I can see some hot air gathering under the hood while sitting at a light. But once the car is moving, the airflow and turbulence under the car will easily pull any hot pocket of air out from under the hood.

I think the placement of the fan would depend on the design of the shroud. IE, how deep are the blades, and how deep is the cylindrical portion of the shroud. Or is it shaped like a venturi, etc. So the drag on the blades may be less or greater in certain circumstances. I think it may be a little premature to turn it into a rule of thumb.

Also, there is a safety concern ... if the fan blades stick out of the shroud, then you need more cage to keep things out of the blades.

 

Spal also builds most of the condenser fans used on industrial refrigeration systems. They are pretty boss.
But, CadKid, No electric fam will do what a properly operating mechanical fan will do. They don't work as well on cooling systems that are not designed specifically for electric fans. I might try using a 190 T-stat. That will give the water more time to cool in the radiator which it will need in a humid environment. Or put a desert water bag on the front. They look cool.

 

Having same kind of problem, ok while moving but temp rose fast when idling. Try connecting your distributor vacuum advance to the vacuum port on the carb, not the ported one. This no cost fix fixed my problem.

(o{}o)

 

My shroud is not cylindrical against the radiator. It opens to the whole size of the radiator. The reasoning is, my fan sits slightly lower, or inline with the lower part of the radiator, but the shroud allows it to pull air through the whole radiator.

On the front of the engine I have belts spinning and a fan turning. I recommend keeping fingers away from this area while the engine is running, shroud or no shroud...

Fan depth in shroud is important. to far in, and it wont work right.....

It was 85 and humid today. I ran at 160 with A/C on....2 core brass/copper....Tomorrow will be about 90 and humid, I will drive it then and see..... I do need to up my thermostats to 180 though...160 is to cool.

 

I agree that it is best to keep yourself out of the action zone entirely. A grill can be a help, though, in case you drop something.

I see what you mean about the shroud. It seems that some shrouds have little to no cylindrical portion. Some have a cylindrical portion that is a few inches deep. Some fans come with their own cylindrical duct. It's generally agreed that SPAL knows what they are doing. Their aftermarket fan comes with a cylindrical shroud with a grill, that you can then attach to a shroud shaped to fit the radiator. http://www.spalusa.com/store/main.aspx?p=itemdetail&item=30102049

That's all I meant - your situation with your fan may not match someone else's.

 

here is an excellent article...

http://www.streetrodderweb.com/tech/1206sr_staying_up_with_the_latest_cooling_system/viewall.html

 

Dang right!
Ported vacuum was 'invented' as an aid to cut emmissions, it will do NOTHING to enhance cooling (or performance).

Retarded timing = heat build-up

 

Just a thought, but there is also more to a fan being in reverse than just the direction of rotation. Sometimes you have to take the blade off and flip it over, as the profile of the blade is specific. (This is only on fans that are designed to be reversible)

I know a guy with a 32 roadster who had two big electric fans, but it still overheated in traffic. The fans were rotating the right direction but the blades were on wrong.

 

The 'Kid' must be out crusin in his cool rod...hasnt been on line for 2 months now

 

Help me out here, maybe I'm my own problem. My 48 DeSoto has vents under the car, in front of the radiator. I installed a deflector "behind" the vent opening, with the idea of catching more air into the radiator (the DeSoto sits very low). Did I do it bass ackwards? Should it/would it be better if I moved the deflectors in "front of the vents?

 

I have been, now looking at that fan in Speedway. Do you prefer the steel rather than aluminum? Why?

Is there any advantage to the HIGH FLOW thermostat Pg 207, item #910-15703?

 

It would be great if people would share the result of all the advice for their problem. Did he fix the problem?

 

It's clear you have an air flow problem. If you installed the fan correctly as in sealed around the rad, you should not be leaking any air that does not get pulled through the rad. SPAL sells a good gasket for sealing the shroud to the rad.

 

I bought the steel because Aluminum has a life span. I also wanted an aggressive pitch all the time. I didn't want it to flatten out at high speed...

I also want to mention HRP recommended this fan, and I find he is an incredible wealth of information. In my case, he was once again right on.

I just took out my High Flow thermostat, The engine will not heat up right. I am runnin a regular 180 degree, and she heats to 160 fast, then slow go to 170 and it stays 170 to 175 with A/C on....85 degree day....

 

Thanks Mustang, I need all the help I can get. I will go with the steel, rather than aluminum, and keep the regular 180 thermostat I just installed. I also have problem with no good outlet for hot air getting from under the hood. I put louvers in the inner fender, doesn't seem to help.
I'm thinking about louvers in the hood, just don't know if I can afford, as the car has excellent paint job, would have to repaint hood, plus cost of louverning.

 

My current setup:





--New radiator, application is mid 70's Dodge truck
--6 blade mechanical
--Converted the electric puller to back up pusher
--Cammed SBC, headers, TH350 (cam is pretty big I think)

On highway, 180F all day long. In very slow traffic, city streets, like if I was sitting in traffic for 20-25 minutes, it's occasionally got to 205 and the electric fan has kicked on. So the car is 100% drivable but does heat up in very slow traffic. I'm going to add a shroud, friend has similar combo he put it together for me, his car runs 10F cooler with a small shroud so I will add one.

 

You need a fan shroud. That should fix your slow traffic overheating problem.

 

Where is the rad for the air-con? I thought they are usually planted right in front the main radiator.

I have a very similar looking radiator to yours on my RPU, and I built a shroud for it recently as it was overheating. It has been pissing with rain most every day, so I haven't got round to driving it and seeing if it makes any difference.

I have been advised that maybe the rad is just not efficient enough to cool a warmed over 350, but a test drive will tell. The tubes/fins do look very sparse compared to late model rads.

 

I'm a little late to the party and as a lot of you already know I am not a proponent of electric fans,,I have used a lot of them in the past but they were marginal at best.

The hottest my old 40 sedan ever ran was when I was using a electric fan and was stuck in a major traffic jam trying to get in the gates at the N.S.R.A Nationals in Columbus, Ohio,,in 1987,,the car was howling!

When I returned home I decide to try anything but a electric fan.

I have also been building and driving Model A's,40 Fords and Deuces for almost 40 years,,so I have encountered a plethora of overheating problems.

I have steel fixed bladed fans on both my Deuces and the Ranch Wagon,,none of them run hot regardless of how long I sit in traffic.

Having a good radiator is also important,,I have used many different manufacturers radiators in the past and have had better luck with the copper brass construction type.

Walker is expensive but I know the quality and have one that is now 19 years old with no problems.

Another thing to address is the water pump pulley and crank pulley,,I have found that buy using a small pulley on the water pump and a larger one on the crank the water moves faster.

BTW,I don't have a shroud on any of my cars,,would it help?,,I can't see why it wouldn't but until I see where I need it I'm not going to worry about it. HRP

 

If you have followed John's build thread I believe that is still in in the things to do list.

As John didn't show a photo from the front of his car with the hood open we couldn't see if he had left the top piece of the stock core support that helps seal off airflow between the core support and hood but the guys swapping to cross flows usually leave that piece off and use a straight length of metal across the top of the radiator allowing massive air flow to go over the radiator rather than through it. The cure there would be to build a panel to cover the space between the front section of the nose and the top of the crossflow to direct air through the radiator rather than over the radiator.

The Dodge truck radiators have been popular ones to use In Mercs and some other older rigs around here for some time. As they can cool a 440 pulling a big camper or trailer keeping a smaller engine in a car cool pretty well/

Going back to the OP's original problem. I can never figure out why a guy pulls off something that works great and puts on something that doesn't work great in it's pace doesn't wake up and decide there in lies his mistake. Custom Mercs should never have their hoods open in public anyhow so ugly under the hood doesn't count. The exception might be the Very cool flathead under the hood of MS Merc or one of the few other fully tricked out engine compartments in Mercs that seem to be the rare exception rather than the norm.

As far as buying an electric fan, The Ford Tarus fans are a known quantity that work, Cad Deville side winder front wheel drive cars have dual fans that are thin and cover a lot of area and pull a lot of air. You also damned seldom hear of an oem radiator cooling fan crapping out unlike the aftermarket fan motors.